Actually, I beat this level following these exact steps:
1. Make all your ships escort you, the Ishiman HVD
2. Build 2 cruisers and a gunship, all escorting you
3. Warp around the station all the way to the enemy planet
4. Once you get there target the planet and build cruisers as you fight
5. Once you have adequate forces at the enemy base, make two cruisers escort you (The Ishiman HVD if it hasn't been destroyed yet. If it has, just go in a crusier) and head back towards you base a warp. Once you get there destroy any enemy ships in the area
6. Build a transport targeted at your base, transfer control to it, and make the cruisesr you came with and your HVD escort you.
7. Target the enemy base, start building cruisers, and go AROUND the enemy base
8. Once you get near to it transfer control to you HVD and let the transport land on the planet.
Thats how I beat that level. Hope my advice helps!
------------------